A WOMAN walks up to an ATM, types in her PIN number, holds her cellphone up to the screen for a few seconds and then walks away. Not very exciting, you may think, but with those simple actions she has set in motion an elaborate quantum protocol that will allow her to shop online with complete confidence.
Thanks to a “quantum ATM” system under development at HP Labs in Bristol, UK, this is now all it will take for two parties to share a secret string of bits via a quantum key distribution (QKD) protocol. That string of bits will be used to verify your identity when you use a credit card…
